1. Field of the Invention
This invention is related to a memory system, especially to a memory system having low read power.
2. Description of the Prior Art
Nowadays, mobile electronic devices are used to perform various kinds of applications, such as watching movie, taking pictures, listening to music . . . , and so on. To support as many applications as possible, mobile electronic devices may require large memory space; therefore, the requirement for large memory space has become critical for mobile electronic devices.
However, as memory size increases, power required for operating memory also increases. For example, when more memory cells are embedded into one single memory bank, each bit line of the memory bank will be coupled to more memory cells. In this case, if one of the memory cells is to be read through one bit line, then the read current generated by the memory cell has to charge all parasitic capacitance of other memory cells coupled to the same bit line. Consequently, the read current may become difficult to identify and the reading speed may be lowered due to the long charging path of the bit line. One solution is to increase the memory current generated by the memory cell, however, the increased memory cell will cause higher read power, conflicting with the low power requirement of the mobile electronic devices.